The present invention relates to vehicle suspensions, and in particular, to a suspension usable in monitoring the weight of a vehicle load supported thereby.
Vehicle suspensions adapted to monitor the weights of bed loads are known. These may be single- or twin-axle suspensions, and may be used in supporting the beds of large vehicles such as trucks or trailers. Typically, in the prior art, in monitoring vehicle load weight, a strain gauge or the like is interposed directly between the vehicle bed and the suspension which supports the bed. In this configuration, bed load weight is transferred directly to the strain gauge. This configuration necessitates the use of expensive and heavy-duty strain gauges, and also frequent replacement of these.
It is a general object of the present invention to provide a vehicle suspension in which the just-mentioned problems associated with measuring vehicle load weight are substantially overcome.
A more specific object of the invention is to provide a suspension in which the supported weight of the vehicle is carried on a flexible beam, deflection of which is related to weight supported by the beam, wherein load weight can be measured according to such deflection.
The suspension of the present invention includes a conventional single- or twin-axle ground-traveling structure. A flexible transversal beam is attached to the structure at a pair of laterally spaced beam points and extends transversely of the bed's longitudinal axis. The vehicle bed is mounted on the beam, at another pair of laterally spaced points generally symmetrical with respect to the first-mentioned pair of points, for journaled pivoting about laterally spaced axes generally paralleling the bed's longitudinal axis and intersecting the beam's longitudinal axis. Such pivoting allows generally uniform beam deflection, substantially in pure bending, between the beam's attachment to the ground-traveling structure, when vehicle load weight is applied to the beam. A strain-sensitive device is mounted centrally on the beam for monitoring beam deflection.
In preferred embodiments, the vehicle bed is attached to the suspension through a pair of stub shafts which are joined to the beam with their axes coincident with the above-mentioned spaced pivot axes. The stub shaft axes also intersect the beam's longitudinal axis. The opposed end portions of each stub shaft, which extend from opposed sides of the beam, are received within a pair of casings, and are journaled therein, with such journaling being accommodated by deformation of an elastomeric bushing interposed between each casing and the associated shaft end portion. The vehicle bed is secured to the casings, with beam deflection being accommodated by counterrotative movement of the two stub shafts relative to the casings.